This type of prosthesis is known from U.S. Pat. No. 8,709,091 B2, which has a microprocessor that uses sensor data to record when the gait cycle has reached the stage at which the joint must be released. The disadvantage of this type of prosthesis is the high level of complexity involved in its production and maintenance.
WO 2014/039885 A1 describes a prosthesis which also records the gait cycle by means of a microprocessor and a number of sensors. It is possible to store threshold values in a control unit of the prosthesis, which are used to control the actuators of the prosthesis. This type of system is also complex to produce and maintain.
US 2014/0074255 A1 describes an artificial foot that uses a rollable element to seal a fluid channel at exactly the point at which the patient is standing. This prohibits a dorsal extension motion of the foot when the centre of gravity is above the foot. The disadvantage of this type of foot is the increased risk of tripping.
US 2014/0330393 A1 describes a foot with two springs that are used to apply a first torque to a dorsal extension motion up to a zero position and then to apply a second torque. The disadvantage of this type of system is the noise emission.
An additional disadvantage of known prostheses is that it is comparatively complex to adapt the prosthesis if shoes with different heel heights are worn.